How much does a 3.00 to 4.99ct I SI1 natural heart diamond cost?

As of October 2026, 3.00 to 4.99ct I SI1 natural heart diamonds typically cost £14,902 GBP to £70,986 GBP, with a median price of £28,950 GBP. There are currently 48 diamonds matching this specification available across retailers.

Where can I find the best price on a I SI1 heart diamond?

About 29% of these diamonds are available at multiple retailers, with an average price spread of 36%. A comparison tool like Carat Hunter lets you see all the prices side by side.

3.00 to 4.99ct I SI1 Natural Heart

Quick answer

As of October 2026, there are 48 natural heart diamonds with I colour and SI1 clarity in the 3.00 to 4.99ct range available across retailers worldwide. Prices typically run £14,902 GBP to £70,986 GBP, with a median of £28,950 GBP. At least 50 retailers stock this exact specification, and 29% of the stones appear at more than one of them, with an average price spread of 36%. Half of all listings fall between £6,158 GBP and £8,798 GBP per carat. The same specification in lab grown form lists at a median of about £769 GBP per carat. Over the last 30 days the median price moved -1.6% and the number of listings moved +13.9%.

Three of the best scored stones at this specification right now:

Caratlytics Diamond Price Index, September 2026: natural diamonds at 2,335 USD per carat and lab-grown at 443 USD per carat, a natural to lab ratio of 5.3 to 1. Heart natural stones in the index: 2,374 USD per carat, +9.8% month on month. See the full index release

Figures come from current listings across more than 100 retailers and refresh daily. The index is a monthly release.

Last updated: October 2026

Available

Lowest Price

£9,575 GBP

Highest Price

£138,392 GBP

Average Price

£38,408 GBP